Canisters filled with uranium byproduct waste are placed in a burial pit at Waste Control Specialists near Andrews, Texas, in this 2009 file photo. Such facilities allow nuclear plants to move their radioactive waste off-site more quickly.

WASHINGTON — The Nuclear Regulatory Commission is rushing a court-ordered evaluation of the risks of storing spent nuclear fuel at the country’s nuclear plants, according to two dozen watchdog groups.

In detailed public comments solicited by the NRC, the groups together contended that the agency’s two-year timeline for an environmental impact statement on the spent-fuel risks is inadequate.

The NRC “would be well-advised to slow it down, quite apart from anybody’s position on nuclear power ... They just don’t have the data,” said Dr. Arjun Makhijani, an electrical and nuclear engineer who is president of the Institute for Energy and Environmental Research. He submitted an expert declaration accompanying the comments from the watchdog groups.

Long-term spent-fuel storage at the nuclear plant sites is now a virtual certainty because there is no federal plan for a national repository. Plans for such a repository at Yucca Mountain, Nev., were withdrawn by the Obama administration in 2010.

Meanwhile, waste-storage pools at many plants are already filled far beyond their original design capacity, and plant operators have been reluctant to convert to more expensive dry cask storage.

Some pools are leaking radioactive water, and a spent-fuel pool fire could be catastrophic, releasing large amounts of radiation.

Many scientists have sounded the alarm about the possibility of an accident or terrorist strike involving the spent-fuel pools. At Japan’s crippled Fukushima nuclear plant, concerns over spent fuel pools continue as Tokyo Electric Power attempts to cover one damaged pool structure, more than a year and a half after the accident.

So the comprehensive risk assessment the groups seek would almost certainly be a powerful weapon in the fight against licensing new plants and relicensing existing plants in the country’s aging nuclear fleet.

But that will take more time, and for some of the watchdogs, that time is a double-edged sword. All reactor licensing and relicensing decisions are on hold during the NRC’s process, meaning that if the process were to take seven to 10 years, as the groups suggest it might, it could amount to a de facto license renewal for that period.

“It’s a concern for us,” said James Musegaas, Hudson River program director for Riverkeeper, a New York organization dedicated to protecting water quality, particularly in the Hudson watershed.

In 2001 Riverkeeper launched an ongoing campaign to close Indian Point Energy Center, a nuclear plant operated by the Entergy Corp., on the Hudson in Buchanan, N.Y. Riverkeeper and others, including New York Gov. Andrew Cuomo, have asserted that the safety record and health and security risks of the plant, within a 50-mile radius of some 17 million people, make relicensing inadvisable.

Licenses for Indian Point’s two operating reactors, Units 2 and 3, expire this September and in December 2015, respectively.

“It’s interesting that you don’t see a lot of public outcry or complaining from the nuclear industry about this process because they benefit if it takes longer,” Musegaas said, referring to the corporations’ legal ability to continue operating the reactors past the renewal deadlines —until the NRC completes the spent-fuel study.

But he added, “While I agree that there’s a risk that if this takes too long Entergy will certainly benefit, causing impacts by continuing to run a plant with current risks we think are too great, I do think the process is worthwhile. The risks with spent-fuel pools are enormous. It’s the biggest safety and security issue at Indian Point, and at other plants.”

According to 2010 statistics gathered by the Department of Energy, Indian Point has more than 1,000 metric tons of spent fuel stored in pools on site.

The U.S. Court of Appeals in Washington, D.C. ruled last year that the NRC’s “waste confidence” rule, a generic presumption that storing spent fuel on nuclear sites is safe, was deficient, and that the possibility of never having a repository had to be considered, along with the risks of leaks and fires in spent-fuel pools.

Environmental lawyer Diane Curran, one of the principal attorneys for the watchdog groups and a key player in the federal case New York v. NRC, admits that a delay benefiting plant operators short-term “is one outcome,” but stresses that a thorough environmental evaluation of the spent-fuel storage risks could be a game-changer across the country in licensing cases.

“Ultimately the agency is going to have to make a decision about whether to renew those existing licenses,” Curran said, “and to some degree it’s an aggregate decision. Do we want to keep generating spent fuel which carries these costs and risks, for which we have no solution?”

After the Court of Appeals decision, NRC chair Allison Macfarlane decided that the NRC would produce a full environmental impact statement in response to the ruling, as opposed to a less rigorous environmental assessment.

According to its web site, the NRC currently has pending applications for 30 new reactors at 19 sites, and Curran pointed out that licensing decisions for those new reactors will also be on hold during the assessment process. “It’s very clear for those reactors that nothing is going to happen” until the environmental impact statement on spent fuel storage is in place, she said.

Makhijani said that in order for the NRC to satisfy the court, “In my opinion it will take well over a decade of work. . . if they keep this schedule the EIS will be speculative and will be shown to be speculative, and they’ll wind up back in court.”

NRC spokesman David McIntyre disputed that assertion, saying, “We are confident we can do a comprehensive report within the two years the commission has given us that will satisfy the court’s remand.” He said the agency has “set up a new “waste confidence directorate” with 20 full-time staff working to procure and analyze the necessary data. “It’s a high priority,” he said, “and we think we’re going to make it” within the two-year timetable.

Curran echoed Makhijani’s view, saying, “Rushing it like this is sure to result in an environmental impact statement that will not be technically sound. The new chairman made a very good call, deciding to do a full environmental impact statement, but it has to be sound.”

If the process does stretch out, Riverkeeper’s Musegaas says, don’t expect his group and others to sit on their hands.

“We’re not just going to sit back and wait for a 10- to 12-year process,” he said. “Within that I think we anticipate having opportunities to try to force a specific review at Indian Point.”

One such factor is a New York State agency’s denial of the plant’s permit to take water from the Hudson. In April 2010, the state denied a water quality certification for Indian Point that is a necessary precursor to relicensing. The denial was appealed by Entergy, and two years of hearings have resulted. That process is expected to wind up in about a year, and if the denial is upheld, Riverkeeper and other such groups could be expected to make the case that, notwithstanding final action on the waste issue, the NRC should deny the relicensing based on the state’s action.